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Quiz 3
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Q.1
Deforestation does not lead to .... .... [C.B.S.E. 1994]
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a) Quick nutrient cycling
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b) Soil erosion
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c) Alternation of local weather conditions
0%
d) Destruction of natural habitat of wild animals
Explanation
Answer : (a)
Q.2
Ecosystem having the highest primary productivity is .... .... [B.H.U.2012]
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a) Pond
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b) Ocean
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c) Forest
0%
d) Desert
Explanation
Primary production is defined as the amount of biomass or organic matter produced per unit area over a time period by plants during photosynthesis. It is expressed in terms of weight (gm-2) or energy (kcal m-2). The rate of biomass production is called productivity. It is maximum where vegetation is maxiumum i.e., forest. Answer : (c)
Q.3
Which is dominant in desert? ..... ..... [B.H.U.1997]
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a) Hyla
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b) Leopard
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c) Tiger
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d) Lizard
Explanation
Out of above options, Lizards are adapted to desert conditions. Thus, population of lizards is dominant in desert. Answer : (d)
Q.4
Trophic levels in ecosystem are formed by .... .... [W.B. 2009]
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a) Only bacteria
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b) Only herbivores
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c) Organisms linked in food chain
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d) Only plants
Explanation
Based on the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level. Answer : (c)
Q.5
Energy flow in an ecosystem is ..... ..... [B.H.U. 2012]
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a) Unidirectional
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b) Bidirectional
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c) Multidirectional
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d) Stable
Explanation
Energy flow is unidirectional. First, plants capture solar energy and then, food is transferred from the producers to decomposers. Answer : (a)
Q.6
Nitrogen content of biosphere remains constant due to .... .... [A.F.M.C.2001]
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a) Nitrogen fixation
0%
b) Nitrogen cycle
0%
c) Industrial pollution
0%
d) Absorption of nitrogen
Explanation
Nutrients such as phosphorus, oxygen, carbon, nitrogen are never lost from the ecosystems, rather they are recycled time and again indefinitely. The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. Answer : (b)
Q.7
Rate of conversion of light energy into chemical energy of organic molecules in an ecosystem is .... .... [C.B.S.E.1998]
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a) Gross primary productivity
0%
b) Net primary productivity
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c) Net secondary productivity
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d) Gross secondary productivity
Explanation
The rate of biomass production is called productivity. Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. Net primary productivity is the available biomass for the consumption to heterotrophs (herbiviores and decomposers). Secondary productivity is defined as the rate of formation of new organic matter by consumers. Answer : (a)
Q.8
Pyramid of numbers in a forest ecosystem is .... .... [M.P.P.M.T.1993]
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a) Upright
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b) Inverted
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c) Irregular
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d) Linear
Explanation
In forest ecosystem Pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores Answer : (a)
Q.9
Domestic cooking gas cylinder contains .... .... [M.P.P.M.T. 1998]
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a) Coal gas
0%
b) Liquid petroleum gas
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c) Non-conventional process
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d) All the above
Explanation
The domestic cooking gas cylinder contains LPG i.e. Liquid Petroleum Gas. LPG is extracted from crude oil and natural gas. Answer : (b)
Q.10
Which is not correct? .... .... [Kerala 2007]
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a) In most ecosystems, the pyramids of number and biomass are upright
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b) In tree dominated ecosystem, the pyramid of numbers is inverted
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c) In deep water ecosystem, the pyramid of biomass is upright
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d) Pyramid of energy expresses mainly the rate of energy production
Explanation
In most ecosystems, all the pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores. Also energy at a lower trophic level is always more than at a higher level. In an ecosystem dominated by trees, the pyramid (of numbers) is of Inverted type because large population of birds and insects depends on small population of trees. The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton. Pyramid of energy expresses mainly the amount of energy produced at a particular level. Answer : (c)
Q.11
Food level of an ecosystem are known as .... .... [M.P.P.M.T.1996]
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a) Producers
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b) Herbivore levels
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c) Consumer levels
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d) Trophic levels
Explanation
Based on the source of their nutrition or food, organisms occupy a specific place in the food chain that is known as their trophic level. Answer : (d)
Q.12
An association which fixes nitrogen through non-nodulation is .... .... [B.H.U.2002]
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a) Maize roots with spirllium notatium
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b) Digitaria roots with spirllium notatium
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c) Coralloid roots of cycas with anabaena
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d) All the above
Explanation
Coralloid roots are specialized roots found in Cycas which are associated with nitrogen-fixing cyanobacteria. Cycads form mutualistic, facultative symbioses with nitrogen fixing cyanobacteria (blue-green algae). Answer : (c)
Q.13
Biomass available for consumption to herbivores and decomposers is called .... .... [C.B.S.E.2010]
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a) Secondary productivity
0%
b) standing crop
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c) Gross primary productivity
0%
d) net primary productivity
Explanation
Net primary productivity is the available biomass for the consumption to heterotrophs (herbivores and decomposers). Secondary productivity is defined as the rate of formation of new organic matter by consumers. Answer : (d)
Q.14
Vegetation of Rajasthan is .... .... [C.P.M.T.1996]
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a) Xerophytic
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b) Alpine
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c) Arctic
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d) Deciduous
Explanation
Rajasthan is a semi-arid to dry habitat area. There are desert in this state. Therefore, vegetation in Rajasthan is xerophytic. Answer : (a)
Q.15
The pyramid of biomass in sea is .... .... [H.P.P.M.T. 2012]
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a) Upright
0%
b) Slanting
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c) Horizontal
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d) Inverted
Explanation
The pyramid of biomass in sea is generally inverted because the biomass of fishes far exceeds that of phytoplankton. Answer : (d)
Q.16
The term biocoenosis was given by ..... ..... [K.C.E.T.2001]
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a) Warming
0%
b) Carl Mobius
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c) Tansley
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d) Odum
Explanation
A biocenosis, coined by Karl Möbius in 1877, describes the interacting organisms living together in a habitat. The use of this term has declined in the 21st сentury Answer : (b)
Q.17
Which one has maximum biomass? .... .... [C.E.T..P.M.T.1997]
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a) Pond ecosystem
0%
b) Lake ecosystem
0%
c) Grassland ecosystem
0%
d) Forest ecosystem
Explanation
The rate of biomass production is called productivity. In forest ecosystems productivity is also high that contributes to maximum biomass. The reason for high productivity is greater number of trophic levels and inclusion of huge population of species is seen in this ecosystem. Answer : (d)
Q.18
Savannahs are .... ..... [M.P.P.M.T.2002]
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a) Tropical rain forests
0%
b) Desert scrubs
0%
c) Grassland with scattered trees
0%
d) Dense forests with closed canopy
Explanation
A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. Answer : (c)
Q.19
The term " ecosystem development" to ecological succession was given by .... .... [Har.P.M.T. 2007]
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a) Odum
0%
b) Clements
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c) Mishra
0%
d) Blackman
Explanation
Eugene P. Odum was an American biologist who gave the term ecosystem development to ecological succession. Answer : (a)
Q.20
At what height in Himalayas are Taiga forest located .... .... [Guj .C.E.T. 2011]
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a) 1000 - 1500 m
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b) 2000 - 3000 m
0%
c) 500 - 1000 m
0%
d) 1000 - 1200 m
Explanation
Taiga (North coniferous forests) are found above 5300 ft (1000-1500 m) altitude chiefly on mountains of Himalaya and Nilgiri. Answer : (a)
Q.21
Which receives the maximum energy .... .... [C.P.M.T.1994]
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a) Producers
0%
b) Decomposers
0%
c) Secondary consumers
0%
d) Primary consumers
Explanation
Pyramid of energy is always upright, can never be inverted, because when energy flows from a particular trophic level to the next trophic level, some energy is always lost as heat at each step. Answer : (a)
Q.22
Which is correct? .... .... [Har.P.M.T..1994]
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a) Least productive ecosystem is desert and deep lake
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b) Sugarcane is the most productive agro-ecosystem
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c) Most productive is coral reef system
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d) All the above
Explanation
Coral reefs are among the most productive ecosystems on the planet, with the primary producers at the base of the food chain (including corals) supporting their complex food webs. Very low productivity is present in deserts and arctic regions. In oceans and other aquatic ecosystems, productivity is limited by light as it decreases with depth. An ecosystem of an agriculture land is called as agroecosystem. Sugarcane is the most productive agroecosystem. Answer : (d)
Q.23
The factor that destroys plant biodiversity is .... ..... [C.E.T. Chd 2002]
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a) Biosphere reserves
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b) Vulnerable ecosystems
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c) Inaccessibility of habitats
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d) Destruction of habitats.
Explanation
The factor that destroys plant biodiversity is destruction of habitats, wildlife species get extinct because of destruction of forest by deforestation. Answer : (d)
Q.24
A food chain begins with .... .... [M.P.P.M.T.1995]
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a) Photosynthetic organisms
0%
b) Nitrogen fixing organisms
0%
c) Decomposers
0%
d) Consumers
Explanation
Starting from the plants (or producers) food chains or rather webs are formed such that an animal feeds on a plant or on another animal and in turn is food for another. The chain or web is formed because of this interdependency. Answer : (a)
Q.25
Detritus food chain begins with .... .... [J.K.C.E.T. 2012]
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a) Primary producers
0%
b) Primary consumers
0%
c) Secondary consumers
0%
d) Dead organic matter
Explanation
The detritus food chain (DFC) begins with dead organic matter. It is made up of decomposers which are heterotrophic organisms, mainly fungi and bacteria. Answer : (d)
Q.26
Which one depicts nitrogen fixation? .... .... [D.P.M.T.1999]
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a) N2 + 3H2 → 2NH3
0%
b) 2NH3 → N2 + 3H2
0%
c) 2N2 + Glucose → 2 animo acids
0%
d) 2NH4 + 2O2 → 8e- → N2 + 4H2O
Explanation
The reduction of nitrogen to ammonia by a living organism is called biological nitrogen fixation. Answer : (a)
Q.27
Which one is biotic in origin? ..... .... [C.P.M.T. 1987]
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a) Texture and porosity of soil
0%
b) Rainfall
0%
c) Carbon dioxide content of soil
0%
d) Light intensity
Explanation
Composition of living organisms, carbon constitutes 49 per cent of dry weight of organisms and is next only to water. Carbon cycling occurs through atmosphere, ocean and through living and dead organisms. Answer : (c)
Q.28
Total energy fixed by an ecosystem is .... .... [C.P.M.T.1991]
0%
a) Primary production
0%
b) Gross production
0%
c) Net production
0%
d) Secondary production
Explanation
Gross primary productivity of an ecosystem is the rate of production of organic matter during photosynthesis. A considerable amount of GPP is utilised by plants in respiration. Gross primary productivity minus respiration losses (R), is the net primary productivity (NPP). GPP – R = NPP Answer : (b)
Q.29
Crop residue allowed to decay and decompose in farm land is called .... .... [C.O.M.E.D.-K’s 2007]
0%
a) Mulching
0%
b) Strip cropping
0%
c) Contour farming
0%
d) Terracing
Explanation
Mulching is a simple process of using garden leftovers such as leaves, grass clipping & shredded trees to cover any bare soil in the garden. The main benefits of mulching are increased water retention, temperature control, and weed prevention. Answer : (a)
Q.30
Mangrove forests occurs in .... .... [Odisha 2003]
0%
a) Laterite soil
0%
b) Estuaries
0%
c) Arid areas
0%
d) Hilly areas
Explanation
Mangrove forests, also called mangrove swamps or mangals, are found in tropical and subtropical tidal areas. Areas where mangroves occur include estuaries and marine shorelines. An estuary is a partially enclosed, coastal water body where freshwater from rivers and streams mixes with salt water from the ocean. Answer : (b)
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